OBJECTIVEThis study was to assess the influence of interaction of combination of immobilized nitrogen cycling bacteria (INCB) with aquatic macrophytes on nitrogen removal from the eutrophic waterbody, and to get insight into different mechanisms involved in nitrogen removal.

METHODSThe aquatic macrophytes used include Eichhornia crassipes (summer-autumn floating macrophyte), Elodea nuttallii (winter-growing submerged macrophyte), and nitrogen cycling bacteria including ammonifying, nitrosating, nitrifying and denitrifying bacteria isolated from Taihu Lake. The immobilization carriers materials were made from hydrophilic monomers 2-hydroxyethyl acrylate (HEA) and hydrophobic 2-hydroxyethyl methylacrylate (HEMA). Two experiments were conducted to evaluate the roles of macrophytes combined with INCB on nitrogen removal from eutrophic water during different seasons.

RESULTSEichhornia crassipes and Elodea nuttallii had different potentials in purification of eutrophic water. Floating macrophyte+bacteria (INCB) performed best in improving water quality (during the first experiment) and decreased total nitrogen (TN) by 70.2%, nitrite and ammonium by 92.2% and 50.9%, respectively, during the experimental period, when water transparency increased from 0.5 m to 1.8 m. When INCB was inoculated into the floating macrophyte system, the populations of nitrosating, nitrifying, and denitrifying bacteria increased by 1 to 2 orders of magnitude compared to the un-inoculated treatments, but ammonifying bacteria showed no obvious difference between different treatments. Lower values of chlorophyll a, COD(Mn), and pH were found in the microbial-plant integrated system, as compared to the control. Highest reduction in N was noted during the treatment with submerged macrophyte+INCB, being 26.1% for TN, 85.2% for nitrite, and 85.2% for ammonium at the end of 2nd experiment. And in the treatment, the populations of ammonifying, nitrosating, nitrifying, and denitrifying bacteria increased by 1 to 3 orders of magnitude, as compared to the un-inoculated treatments. Similar to the first experiment, higher water transparency and lower values of chlorophyll a, COD(Mn) and pH were observed in the plant+ INCB integrated system, as compared to other treatments. These results indicated that plant-microbe interaction showed beneficial effects on N removal from the eutrophic waterbody.

Biodegradation, Environmental ; Eutrophication ; physiology ; Magnoliopsida ; metabolism ; Nitrogen ; isolation & purification ; pharmacokinetics ; Systems Integration ; Water Microbiology ; Water Pollutants, Chemical ; isolation & purification ; pharmacokinetics ; Water Purification ; methods

OBJECTIVETo understand the current status of disease burden caused by gastric cancer in Jinchang cohort.

METHODSIn this historical cohort study, the data of gastric cancer deaths from 2001 to 2013 and the medical records of gastric cancer cases from 2001 to 2010 in Jinchang cohort were collected to analyze the mortality, potential years of life lost (PYLL), working PYLL (WPYLL) associated with gastric cancer, and the medical expenditure data were used to evaluate the direct economic burden. Spearman correlation analysis and the average growth rate were used to describe the change trend of disease burden of gastric cancer.

RESULTSA total of 213 gastric cancer deaths occurred in Jinchang cohort from 2001 to 2013. The average annual crude mortality rate of gastric cancer was 38.30 per 100,000 in Jinchang cohort during 2001-2013 and no obvious change was observed. The crude mortality rate in males was 6.84 times higher than that in females. Gastric cancer death mainly occurred in age group 50-79 years (82.62%), while the mortality rates was increasing among the people under 50 years with an average annual increase rate of 0.77%. The annual average PYLL (APYLL) and average WPYLL (AWPYLL) caused by gastric cancer decreased by 8.43% and 10.46%, respectively. No obvious change in medical expenditure of gastric cancer cases was observed in Jinchang Cohort during 2001-2010, and the medical expenditure and average daily cost of hospitalization were 8102.23 Yuan, and 463.45 Yuan per capita, respectively.

CONCLUSIONSThe burden of disease for gastric cancer was heavy in Jinchang cohort. The PYLL and WPYLL had no change, while the APYLL and AWPYLL showed a increasing trend during the last ten years. Direct economic burden of inpatients with gastric cancer had no change.

Aged ; China ; epidemiology ; Cohort Studies ; Cost of Illness ; Female ; Health Expenditures ; statistics & numerical data ; Hospitalization ; economics ; Humans ; Male ; Middle Aged ; Stomach Neoplasms ; economics ; mortality